The present invention relates to a marine propeller structure.
In the state of the art, in order to produce a propeller firstly a model of the propeller is made and then the whole propeller is casted into this mold by preparing molds from this model. The propeller is roughly formed when it is removed from the mold. A homogeneous structure is not formed in the propeller removed from the mold and in order that the propeller is put into its final form it must be processed by machine or manually after the process of removal from the mold. Processing capacities of precision machines are variable. Therefore, difficulties are experienced in finding a device so as to process the propeller according to propeller sizes. Processing of overlapped blades is very difficult; this structure is bulky and very prone to error formation. For this reason, propellers removed from the mold have to be processed by hand machines in most cases. While the propeller is being processed, desired objectives cannot be achieved for 100 percent and this leads to loss of performance in propellers.
Due to all said disadvantages mentioned, production of propeller blades separately is possible as well. After the separated propeller blades produced are put into their final form by precision machines, they are assembled using various connection members (6) and additional fasteners and enabled to form the propeller.
Some applications in the state of the art are disclosed in the United States patent documents no. US2008/0166933A1 and no. US6537031B1, the Great Britain Patent document no. GB2328251A and the Chinese utility model no. CN2248162. In the said applications, propeller structures wherein the blades can be attached/detached to/from the propeller are disclosed. Propellers are formed by attaching the blades to a central hub by means of connection members (6) in the said propellers.
The Japanese patent document no. JP 1237068 (A), another application in the state of the art, discloses blades which form a propeller by means of a central hub again and production method of these blades and separate molding of these propeller blades. The blades removed from the mold are mounted to a central hub.
The Great Britain Patent document no. GB 2264983 discloses a propeller structure with no central hub. In the said propeller, the blades are fastened to an outer ring.
With the applications in the state of the art, problems arising from shapes, positions and size of overall dimensions of the propeller blades, in the molding process are eliminated. However, the blades are fastened to a body such as a central hub by means of connection members (6) due to disintegration risks originating from the centrifugal force created by the blades during rotation of the propeller. Maximum 4 blades can be attached to these hubs. In addition, surface area ratio regarding performance of the propeller in these propellers is close to 1/1 or less than this ratio.